Method of applying plaster or stucco



Feb. 23 1926.

W. H. ALTON METHOD OF APPLYING PLASTER 0R STUCCO Filed AuguSt 15, 1925 INVENTOR Patented Feb, 23, 1926.

UNITED I STATES PATENT OFFICE.

WILLIAM H. ALTON, OF NEW YORK, N. Y., ASSIGNOR..TO R. T. VANIJERBILT COM- PANY, OF NEW YORK, N. Y., A CORPORATION OF NEW YORK.

METHOD OF APPLYING PLASTER OR STUCCO.

Application filed Augustv 13, 1925. Serial No. 49,941.

To all whom it may concern: I

Be it known that I, WILLIAM H. ALTON,

a citizen of the United States, residing at- New York, "county of New York, and State of New York, have invented a certain new and useful Improvement in Methods of Aplying Plaster or Stucco, of which the folowing is a clear, full, and exact description.

This invention relates to an improved method of applying stucco, plaster and the like to walls and ceilings of buildings and other structures. It is one of the objects of the present invention to provide a simple and effective method of applying stucco or plaster to surfaces without the use of metal or wooden lath.

It is one of the advantages of the present invention that surfaces, whether smooth orrough, can be treated to form a waterproof coating which is capable of firmly holding stucco or plaster and which covers the surface to be plastered smoothly and uniformly and prevents moisture or chemicals from the plaster or stucco from penetrating into the 1 surface so treated,

=wooden lath is employed the tongues of plaster or stucco protruding between the aths are relied on to hold the plaster or stucco. In practice the plaster or stucco is wet when applied and the lathe absorb moisture with the resulting swelling of the wood and on drying out shrink away from the plaster. or stucco tongues tending to crack or break the tongues andpermitting the plaster or stucco to be easily loosened.

Metal lath which is used to a large extent with stucco is easily attacked by the chemicals in stucco or plaster, such as for example chlorides, and when the stucco is applied to structures which come in contact with salt spray the absorbant character of the stucco causes it to absorb considerable quantities of salt water which in turn attacks the metal lath causing it to rust and finally resulting .in cracks and breaks in the stucco surface.

It has been proposed to overcome the defects of metal and wood laths by using contlnuous sheets of fiber or felt or paper sat- ,urated with bituminous materials and simllilI waterproof sheets which are provided with transveise strips of wood resembling the ordinary wood lath. The whole fabric is delivered in rolls and is nailed on the walls in place of wooden lath. It has also been proposed to.form a rough surface on felt or paper by embedding gravel into the soft surface of the bituminous binder, with which the paper or felt is coated or impregnated. These waterproofed sheet laths are superior to the ordinary wood and metal lath but are still subject to numerous 'disadvantages. Wheretransverse wooden strips are used the expansion and contraction of the wooden strips causes loosening of the plaster as in the case of ordinary wooden lath. Further serious disadvantages of sheet lath lie in the fact that it is necessary to nail or otherwise fasten the sheet to the wall on which it is to be used. This practically restricts its utility to walls of wood or composition Which will take nails as it is diflicult or impossible to faster the sheet to metal or brick walls satisfactorily. Moreover the sheet is continuous only where the walls are straight and smooth and of substantially rectangular shape. -Where the walls are of unusual shape or are uneven the sheet must be cut with the resultant joints or skilled labor, and, where the walls are of unusual shape there is much loss in cutting the sheet. It is also difficult or impossible to apply the relatively stiff sheet-lath perfectly evenly and pockets may, and usually do occur between the wall and the sheet. These pockets or gutters may become filled with water which expands on freezing and tends to crank the stucco or plaster,

In my prior application, Serial N 0. 41,947, filed on July 7, 1925, I have described an improved method of applying stucco or plaster by forming a smooth uniform and continuous sheet of waterproof plastic on the walls or other structure to he plastered and applying to this plastic sheet fine gravel,

the influence of moisture and it forms a com-- coating rather than to the coarse sand, crushed stone, glass, cork or similar granular substances while the coatmg is still soft.

v After hardening the coating presents a' uniform. continuous roughened surface which readily takes plaster or stucco and retains it indefinitely as'there is no tendency of the coating to expand or contract under plete protection for the underlying wall.

The present invention is an improvement on my prior application and consists in combining two of the operations there described into a single operation. Instead of apply ing a film or coating of plastic and, then embedding granular substances therein I have found that it-is possible to mix the granular substances with the plastic before applying so that the coating instead of being a simple coating is-a rough coating which, on drying, takes plaster readily. This was all the more suprising in view of the fact that'a smooth plastic coating con I prior application referred to above. In the first place, the labor is considerably lessened as it is not necessary to first apply a coating andthen embed the granular material therein and one operation is thereby avoided. A further and even i more important advantage lies in the fact that by incorporating the granular material into the plastic before coating I am able to achieve a very great reduction in the amount of plastic required as the granular material acts not only 'as a roughener to cause adhesion of plaster or stucco but also acts as a filleror extender making it possible to cover a much greater surface with the same amount of plaster. Since the plastic materials used are by far the most expensive ingredients entering into the plaster basethe present invention effects a very notable saving in cost of material. I have found, for example, that for coating straight walls less than half the amount of plastic required by the process of my prior application can .be effectively used when granular material is incorporated with it before applyin ,the coating.

The plastics w ich may be used in the present invention may be any suitable waterproof plastic but I prefer to use pitches,

aeraee'? such as stearine pitch and. the like and bitumens such as tar, asphalt and their de- The bituminous plastics may be applied in general in 3 different ways. The plastic may be rendered fluid or semi-fluid by means of heat the granular material mixed in and the hot mixture applied to the walls by "brushing, spraying or other means, or the plastic may be rendered liquid or semiliquid by the use of suitable solvents. The combination of heat and solvents may, of course, also be used in thecase of hard pitches. I have found however that bituminous plastics can be most effectively used in the form of water emulsions and I will.

describe the invention more in detail in connection with the use of water emulsions of bituminous plastics which may be applied cold and which can be readily brought to the proper consistency to hold the granular material in an evenly distributed form. The water emulsions may be prepared by the addition of emulsifiable gums and resins and other emulsifying or deflocculating agents. I have found that water emulsions of asphalts or similar bituminous plastics made by means of finely divided colloidal clay as an emulsifying agent with or with out the addition of other defiocculating agentsare particularly'suitable and constitute the preferred type of bituminous plastic.

The granular substanceswhich may be used include almost any granular substance which is not affected by moisture, such as fine gravel, coarse sand, crushed stone, glass, ground cork, crushed slag, both natural and artificial and other similar vitrified products. Fibrous material, such as short fiber asbestos, may also be added to increase the strength of the coating.

The invention will be more particularly described in the following specific example in connection with the accompanying drawings, in which- Figure 1 IS a perspective view of a portion of a stucco wall with the stucco and rough coating partly broken away; and

- Figure 2 is a cross section through a 'wall stuccoed according to the present invention,

the section being taken along the line 2-2 of Figure 1, and being on a somewhat larger scale.

The wall is show n\at 1,- the waterproof plastic and granular material coating at 2 and the stucco or plaster at 3.

In preparing a preferred water emulsion of bituminous plastic 92 parts of asphalt, 8 parts of colloidal clay and a small amount of soap are ground together in about 200 parts of water until they "form a viscous liquid or thin paste. The emulsification can advantageously be accelerated by the use of moderately elevated temperatures. The paste may be thickened by adding fine sand, asbestos fiber or other inert filler, or in certain cases may require thinning with water in order to produce the correct consistency.

1 part of volume of the water emulsion is then thoroughly mixed with 4 parts of volume of granular material, for example, fine gravel which may advantageously be of roughly uniform size passing an eight mesh sieve and being retained by a twenty mesh sieve.

After the-granular material is thoroughly incorporated so that the granules are evenly covered with the plastic asphalt the mixture is then applied to the wall or surface by means of a trowel, brush, cement gun or other suitable device, to form a layer oi the desired thickness. The coated wall is then allowed to stand until it is dried, which period may range from a few hours to several days, depending on weather conditions, nature of the paste or thickness of the layer. \Vhen dried, the asphalt forms a hard continuous.waterproof coating with a roughsurfaee of coated gravel. Plaster or stucco is then applied in the usual manner but in general the amount of stucco or plaster used is very much less than with ordinary Wood or metal lath, since there are no large crevices to be filled up. The plaster or stucco Wall presents a smooth and uniform appearance and the plaster or stucco will adhere indefinitely.

In the specific example above I have described the use of gravel containing particles between eight and twenty mesh. This size of particles I have found to be very effective for ordinary applications of plaster and stucco but it shouldbe understood that the invention is not limited to a particular size of granular material and for some purposes I may use a considerably finer material which may be classed as coarse sand and may run as fine as fifty mesh or finer. In some cases, particularly where a very thick, strong layer of concrete is required, as in the case of certain piers which are lined with concrete, it is desirable to use a larger size of aggregate. In general, however, I find that inch is about the limit for practical purposes as it is dillicult to form a homogeneous coating with aggregates which are larger owing to the fact that the heavy granules tend to sink to the bottom. In certain extreme cases, by using a viscous plastic, aggregates as large as 1 inch may be used but for most purposes such extreme sizes are less desirable.

In general, it is advantageous to use aggregates of approximately uniform size, as the surface formed, particularly where the waterproof plastic coating is thin, is more even and a better adherence of the concrete and plaster is had than where the granules are of widely varying sizes.

. In the example I have described the use p of approximately four times as much aggregate as plastic. I have found that with a water emulsion of asphalt prepared as described in the example, these proportions give an excellent result but it should be understood that the invention is not limited to these proportions and they may be varied widely particularly when different plastic coatings are used.- In general, of course, a maximum amount of granular material should be used, as the cost of the coating is thereby greatly reduced.

In the claims the word plaster is used in a broad sense to cover stucco and similar cement mixtures.

What I claim as new is- 1. A method of plastering surfaces which comprises applying thereto a viscous coating containing a mixture of bituminous plastic and granular material to provide a rough surface and applying plaster thereto.

2. A'method of plastering surfaces which comprises applying thereto a viscous coating consisting in a mixture of a water emulsion of bituminous plastic and granular ma terial to provide a rough surface, permitting the coating to harden and applying plaster thereto.

3. A method of plastering surfaces which comprises applying thereto a viscous coating consisting in a mixture of water emulsion of bituminous plastic containing colloidal clay admixed with granular material, and applying plaster to the rough surface thus produced.

Signed at New York city, N. Y., this 11th day of August 1925.

WILLIAM H. ALTON. 

